I have to say I was a bit wary of getting the book. Both Inkscape and GIMP cookbooks by PacktPub were considerably below expectations, especially the latter which had tons of rewrites of existing tutorials on GIMP.

The cookbook by Enrico Valenza is an entirely different story. First and foremost, it clearly aims at people who are already familiar with the basics on 3D modeling and rendering, but only started grokking Cycles. There's no typical introduction to Blender's user interface which is good in this case.

Coverage

"Blender 2.6 Cycles: Materials and Textures Cookbook" is divided into several parts:

In the first chapter Enrico explains the basics of setting up materials for objects, world, and lighting. He also gives some useful advices about minimizing the amount of "noise" in the Rendered viewport.

The second chapter deals with the management of materials. Enrico suggests to give them self-explanatory names and reuse them from saved .blend files as much as possible. I absolutely loved how Enrico made a point of keeping nodes organized: pretty much every screenshot is lacking chaotic noodles that you can often see on various Blender videos online. Instead he consistently organizes nodes into groups and adds captions. That's the kind of workflow that really should be promoted.

The rest of the chapters cover creating natural, complex natural and man-made materials and are structured in pretty much the same way:

Getting ready section, where you prepare a scene.

How to do it section, where you follow the recipe.

How it works section, where the author explains the techniques used in the recipe.

Some of the recipes don't follow this structure: e.g. there's no How it works explanation for the rubber material. At the same time Enrico add useful hints and advices here and there which amounts to a lot.

The scope of materials covered in the book is large enough. You will learn to setup materials for rocks (both procedurally and with textures), snow, ice, running water, various plastic and metallic objects, organic materials like leather and serpent's skin, but also — ocean, underwater environment, snowy mountain landscape, realistic planet Earth as seen from space etc.

Impressions

Enrico meticulously described every step, so I found following the recipes easy enough (the books also comes with a digital download of all the scenes used in recipes).

My only major gripe about the book is that uses too simplistic scenes for demonstrating the results. E.g. the section on rubber materials could do with a tire instead of Suzanne. The same pretty much applies to most recipes.

Conclusions

This isn't the first book on Blender that covers Cycles. Most recently "Blender Master Class" by Ben Simonds introduced the basics of using both Blender Internal and Cycles, and Tony Mullen focused on Cycles in the second edition of "Mastering Blender".

However, so far this is the only dedicated Blender Cycles book, and it's a good one at that.

If you are only starting out with Blender, I would recommend getting yourself one of the recent books like the aforementioned "Blender Master Class" as well for covering most angles regarding modeling, texturing, and rendering.